Sequentially switched bulk acoustic wave (BAW) delay line circulator

Abstract

A sequentially switched bulk acoustic wave (BAW) delay line circulator is disclosed herein. A circulator circuit is implemented with semiconductor components in order to provide a compact, low cost solution for simultaneous signal transmission and reception over a single antenna. For example, the circulator circuit can include a transmit (TX) port, a receive (RX) port, and an antenna port. Antenna switching circuitry selectively couples the antenna port to two or more BAW delay lines, and TX/RX switching circuitry selectively couples the BAW delay lines to the TX port or the RX port. The BAW delay lines function as memory to store TX and RX signals long enough for the antenna switching circuitry, a TX switch, and a RX switch to be switched in sequence and route the TX signals from the TX port to the antenna port and route the RX signals from the antenna port to the RX port.

What is claimed is: 
     
       1. A semiconductor-based circulator circuit, comprising:
 a transmit (TX) port; 
 a receive (RX) port; 
 an antenna port; 
 a first bulk acoustic wave (BAW) delay line; 
 a second BAW delay line; 
 antenna switching circuitry coupled between the antenna port, the first BAW delay line, and the second BAW delay line and configured to selectively connect the antenna port to the first BAW delay line or the second BAW delay line; and 
 TX/RX switching circuitry configured to:
 selectively connect the TX port to the first BAW delay line or the second BAW delay line; and 
 selectively connect the RX port to the first BAW delay line or the second BAW delay line; 
 
 wherein each of the first BAW delay line and the second BAW delay line introduces a signal delay time which is greater than a switching time of the antenna switching circuitry. 
 
     
     
       2. The semiconductor-based circulator circuit of  claim 1 , wherein the semiconductor-based circulator circuit is a full duplex circulator. 
     
     
       3. The semiconductor-based circulator circuit of  claim 1 , wherein the TX/RX switching circuitry comprises:
 a TX switch coupled between the TX port, the first BAW delay line, and the second BAW delay line and configured to selectively connect the TX port to the first BAW delay line or the second BAW delay line; and 
 a RX switch coupled between the RX port, the first BAW delay line, and the second BAW delay line and configured to selectively connect the RX port to the first BAW delay line or the second BAW delay line. 
 
     
     
       4. The semiconductor-based circulator circuit of  claim 3 , wherein the TX switch and the RX switch are simultaneously switched, such that:
 when the TX switch couples the TX port to the first BAW delay line, the RX switch couples the RX port to the second BAW delay line; and 
 when the TX switch couples the TX port to the second BAW delay line, the RX switch couples the RX port to the first BAW delay line. 
 
     
     
       5. The semiconductor-based circulator circuit of  claim 1 , wherein the switching time of the antenna switching circuitry is between 0.5 nanoseconds (ns) and 50 ns. 
     
     
       6. The semiconductor-based circulator circuit of  claim 1 , wherein the antenna switching circuitry comprises a semiconductor switch. 
     
     
       7. The semiconductor-based circulator circuit of  claim 6 , wherein the antenna switching circuitry comprises a gallium arsenide (GaAs) transistor-based switch. 
     
     
       8. The semiconductor-based circulator circuit of  claim 6 , wherein the antenna switching circuitry comprises a gallium nitride (GaN) transistor-based switch. 
     
     
       9. The semiconductor-based circulator circuit of  claim 1 , wherein the antenna switching circuitry comprises a silicon-on-insulator (SOI). 
     
     
       10. The semiconductor-based circulator circuit of  claim 1 , wherein each of the first BAW delay line and the second BAW delay line comprise a BAW resonator. 
     
     
       11. The semiconductor-based circulator circuit of  claim 1 , wherein:
 the TX port is coupled to TX processing circuitry; and 
 the RX port is coupled to RX processing circuitry. 
 
     
     
       12. A radio frequency (RF) transceiver, comprising:
 transmit (TX) processing circuitry; 
 receive (RX) processing circuitry; 
 an antenna; and 
 a circulator circuit configured to simultaneously exchange a RX signal between the antenna and the RX processing circuitry and exchange a TX signal between the TX processing circuitry and the antenna, comprising:
 a first bulk acoustic wave (BAW) delay line; 
 a second BAW delay line; 
 antenna switching circuitry coupled between the antenna, the first BAW delay line, and the second BAW delay line; and 
 TX/RX switching circuitry coupled between the TX processing circuitry, the RX processing circuitry, the first BAW delay line, and the second BAW delay line; 
 
 wherein each of the first BAW delay line and the second BAW delay line introduces a signal delay time which is greater than a first switching time of the antenna switching circuitry and a second switching time of the TX/RX switching circuitry. 
 
     
     
       13. The RF transceiver of  claim 12 , wherein at a first time:
 the antenna switching circuitry couples the RX signal from the antenna to the first BAW delay line; and 
 the TX/RX switching circuitry couples the TX signal from the TX processing circuitry to the second BAW delay line. 
 
     
     
       14. The RF transceiver of  claim 13 , wherein at a second time after the first time:
 the antenna switching circuitry couples the TX signal from the first BAW delay line to the antenna; and 
 the TX/RX switching circuitry couples the RX signal from the second BAW delay line to the RX processing circuitry. 
 
     
     
       15. The RF transceiver of  claim 14 , wherein the signal delay time occurs between the first time and the second time. 
     
     
       16. A method of operating a radio frequency (RF) transceiver, comprising:
 coupling transmit (TX) processing circuitry to a first bulk acoustic wave (BAW) delay line; 
 coupling an antenna to a second BAW delay line using antenna switching circuitry; 
 after a first delay, coupling the antenna to the first BAW delay line using the antenna switching circuitry; and 
 after the first delay, coupling receive (RX) processing circuitry to the second BAW delay line; 
 wherein each of the first BAW delay line and the second BAW delay line introduces a signal delay time which is greater than a switching time of the antenna switching circuitry. 
 
     
     
       17. The method of  claim 16 , further comprising:
 storing a first TX signal in the first BAW delay line during the first delay; and 
 storing a first RX signal in the second BAW delay line during the first delay. 
 
     
     
       18. The method of  claim 17 , further comprising:
 storing a second TX signal in the first BAW delay line during a second delay after the first delay; 
 storing a second RX signal in the first BAW delay line during the second delay after the first delay; 
 after the second delay, coupling the antenna to the first BAW delay line; and 
 after the second delay, coupling the RX processing circuitry to the first BAW delay line. 
 
     
     
       19. The method of  claim 17 , further comprising:
 storing a second TX signal in the second BAW delay line during a second delay after the first delay; 
 storing a second RX signal in the first BAW delay line during the second delay after the first delay; 
 after the second delay, coupling the antenna to the second BAW delay line; and 
 after the second delay, coupling the RX processing circuitry to the first BAW delay line.